fix(issue-18): the wrapper's subscriber waits for the first event up to the wall clock

The subscriber is started before the injection, and the injection itself
(idle handshake, quiescence, delivery grace) can take tens of seconds, so
a first-event budget of T + K x N measured from the subscription could
expire before `started` was even possible. The wrapper now passes
--ack-timeout <wall clock>: it judges delivery with _wait_started (T from
the injection) and reaps the subscriber on failure; K x N applies from the
first event on. A standalone subscriber keeps T + K x N. Documented in
MESSAGING.md 4.3.

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01VCgu9Fa9iT7TbJUSzdq4Ff

.agents/skills/multi-agent-mux-delegate-job/multi-agent-mux-delegate-job

@@ -228,7 +228,11 @@ EOF
 
     # 3) START THE SUBSCRIBER
     local logf="$REGISTRY_DIR/$JOB_ID.subscriber.out"
-    local sub_extra_args=()
+    # Before the first event the subscriber is bounded by the wall clock only:
+    # delivery (T from the injection, which happens after the subscriber is
+    # up and can take a while itself) is judged by _wait_started, and a failed
+    # injection reaps the subscriber. From the first event on, K x N applies.
+    local sub_extra_args=(--ack-timeout "$TIMEOUT")
     [ -n "$_disp_tok" ] && sub_extra_args+=(--expect-dispatch-token "$_disp_tok")
     _is_remote "$AGENT_SESSION" && sub_extra_args+=(--remote)
     "$PY" "$SCRIPT_DIR/scripts/job_subscriber.py" --registry-dir "$REGISTRY_DIR" \
@@ -401,7 +405,7 @@ EOF
 
       # Start subscriber
       local logf="$REGISTRY_DIR/${JOB_ID}.iter_${iteration}_${display_role}.subscriber.out"
-      local loop_sub_args=(--attempt-id "$attempt")
+      local loop_sub_args=(--attempt-id "$attempt" --ack-timeout "$TIMEOUT")
       [ -n "$_disp_tok" ] && loop_sub_args+=(--expect-dispatch-token "$_disp_tok")
       _is_remote "$current_session" && loop_sub_args+=(--remote)
       "$PY" "$SCRIPT_DIR/scripts/job_subscriber.py" --registry-dir "$REGISTRY_DIR" \